


Undying Undyne II

by UndyingUndyneTheUndying (FlyingUnhindered)



Series: Undying Undyne II [2]
Category: Undertale (Video Game)
Genre: Determination (Undertale), Determination can break science, Gen, Humanity doesn't get destroyed, MK the Undying, Male Frisk (Undertale), Monster evacuation by MK, Monster with two monster souls, References to Undertale Genocide Route, Snowdin Forest, lots of determination, mysterious door
Language: English
Status: Completed
Published: 2019-06-28
Updated: 2019-07-01
Packaged: 2021-02-25 21:02:20
Rating: General Audiences
Warnings: Major Character Death
Chapters: 5
Words: 14,542
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21621928
Author URL: https://archiveofourown.org/users/FlyingUnhindered/pseuds/UndyingUndyneTheUndying
Summary: Monster Kid tries to be like Undyne and stands up to the human, who has been killing almost everyone on sight. When the human attacks him, Undyne jumps in and takes the blow. She tells him to leave, and he obeys. But after a couple seconds of thought, he turns back to watch Undyne beat up the bad guy.Only, she's the one who gets beaten up.
Relationships: Monster Kid & Alphys, Monster Kid & Asgore, Monster Kid & Monster Kid's Father, Monster Kid & Monster Kid's Mother, Monster Kid & Undyne (Undertale)
Series: Undying Undyne II [2]
Series URL: https://archiveofourown.org/series/1590895
Comments: 3
Kudos: 16





	1. Undyne the Dying

**Author's Note:**

> "Undying Undyne II" is meant to be read as "Undying Undyne the Second," but "Undying Undyne 2" works as well.
> 
> This story originally began when I heard about how Undyne became Undyne the Undying. It started my wheels of imagination turning, and by the next day (June 28) I had started a three-day writing spree (not counting June 30) with the end result being what you could call the rough draft. Since then I have edited it many times, doing anything from grammar edits to adding Doge into the evacuation scene. I say that the rough draft was completed on July 1 because I have not added anything more major than Doge since then. It was originally posted on AO3 over the course of a month from late November 2019 to late December 2019, but has now been backdated to reflect when it was actually written. 
> 
> One other thing: Determination is the answer to everything.

There was a joke around Snowdin that if the King was bad at names, then MK’s family didn’t know names were. In fact, when they had their first child, they named him Monster Kid, or MK for short. He was just like them - yellow, armless, and with spikes on his head. He ran almost everywhere he went, and as he didn’t have arms, he fell all the time.

This didn’t stop him from running; sometimes it seemed that, the more he fell, the more he ran. Although he was a naïve monster, he was only a few years from being an adult, for this kind of monster matured quickly from child to adult in only a year or two, sometimes faster. The time between newborn and adult was often 3-4 years, depending on the monster.

Lately there had been talk about a human, who was ruthless and killed almost anyone on sight. But MK felt safe. He lived in Snowdin Forest, and the human had yet to explore that area. They even held school on a regular basis - as regular as it could be with the constant fear of the human.

But MK had never seen the human. Undyne was his hero; she would surely beat him up. Undyne was his role model, his favorite monster in all of the Underground. He had only seen her once or twice that he could remember, but that didn’t stop him from making her his idol.

Mom said it was dangerous outside the forest; Dad didn’t want him venturing anywhere near the outskirts of the forest. He said that “If that human sees a monster in the forest, he will try to kill it; if it runs deeper into the forest, he will pursue and find us all.”

However, MK was still just a kid, and the warnings flowed in one ear and out the other. He was old enough to start maturing, but that hadn’t happened yet. It was like a growth spurt; it happened to everyone, but not at the same time or for the same length of time.

Right now he was in bed, lying on his back, thinking. The way he saw it, Undyne was not going to come to Snowdin Forest unless there was trouble. If there wasn't any trouble, she wouldn’t come. MK desperately wanted to see his hero again. Soon he would be mature and have to stay at home to help his parents or his relatives with adult stuff like taking care of his younger sister. Then he would never have a chance to go see her.

That left now. His only chance to see her would be now. And what better time than night? Nobody would see him sneak out, not even the human.

MK sat up with more caution than usual. His parents were asleep; he could tell by their snores - one high pitched and slightly irregular, the other deep and powerful. Slowly he swung his feet to the floor and stood, making sure the floorboards didn’t creak. Despite the builders having no arms, the house was quite cozy.

For once Monster Kid didn’t run, but stealthily crept out of the house. If Mom was to catch him, he would be in big trouble, especially once she knew why she was leaving. If Dad was to catch him, he would be in even bigger trouble. 

Even when he was away from the house MK didn’t run. There were too many sticks to avoid. Outside of the forest he slid on the ice leading to Waterfall. He didn’t start running because there was another monster to talk to. He was a fish monster, although he didn’t resemble Undyne. He stood by an echo flower, talking about how explaining them was his only life purpose. There was a stand or lookout post beside the monster and the flower, but it was empty.

Then came another monster, going the same way he was going. 

“Yo!” MK said. “You're a kid too, right? I can tell 'cause you're wearing a striped shirt.” Then he thought of something else. “Yo, everyone ran away and hid somewhere. Man, adults can be so dumb sometimes, haha... Don't they know we've got Undyne to protect us!?” The monster didn’t answer, but MK fancied that he looked slightly interested. So he kept talking. “Yo! Are you sneaking out to see her, too? Awesome... she's the coolest, right!?” He didn’t give his new friend a chance to answer as he bubbled over in praise for her. “I wanna be just like her when I grow up... Hey, don't tell my parents I'm here. Ha ha.” The monster started walking, and MK followed. There was a box with a sign by it, then a river to cross. They walked through some grass, and he got his first glimpse of Undyne, standing above them, apparently expecting someone, but nobody came. At one point she stared directly at the other monster in the grass, but her helmet hid the expression on her face.

“Yo... did you see the way she was staring at you...?” he asked the other monster after Undyne left. “That... ... was AWESOME! I'm SOOOO jealous! She was just standing there waiting FOREVER, and then you just...!!! C'mon! Let's go watch her beat up some bad guys!”

MK started to run. He tripped, fell flat on his face, struggled upright, and kept going. He fell often, but that did nothing to deter his determination to see Undyne. He must have gone ahead of the other monster, but found him again after some time. They entered more grass, and MK saw his idol again. She stood above them, spear in hand, ready to throw at them. After a long time, she put it away and left. He was disappointed, but only until he heard her clanking armor coming closer. She stepped into the grass, reached down, and pulled him up by the face. He could barely restrain himself from wriggling in pure joy. Undyne looked at him for some time, then put him back down and left.

“Yo... did you see that!?” The other traveller didn’t look extremely interested, but he didn’t say to shut up, so MK continued gushing. “Undyne just... ... TOUCHED ME!” he cried. “I'm never washing my face ever again...! Man, are you unlucky,” he told his fellow monster. “If you were standing just a LITTLE bit to the left...! Yo, don't worry! I'm sure we'll see her again!”

He ran and tripped again, but was soon back on his feet and moving again. They moved on. MK saw a statue sitting in the rain. There was a sign that requested that you take an umbrella, but the other monster didn’t and MK couldn’t, so they walked in the rain. He ran through the puddles, always walking beside or behind the monster. They turned the corner, walked down a long, rainy hallway - the other monster didn’t seem to be in a hurry to see Undyne, turned another corner, and stepped into an area where you could look across the marsh and see the capital, New Home. Despite wanting to hurry and see Undyne, MK stopped and stared. He had never seen this before.

The other monster kept walking, neither looking back nor waiting for him. After a moment of silent awe, MK ran and caught up to him. A few minutes later the path hit a dead end. If either of them had been taller, they would have been able to climb up, but neither of them were tall enough. He thought about telling the monster about how cool Undyne was, or maybe about the time when the King came to school, but he remembered he’d already said that.

“Yo, this ledge is way too steep… Hmm... Yo, you wanna see Undyne, right...?” The monster didn’t answer, and MK took it as a yes. “Climb on my shoulders.” He climbed on, and it hurt. “Owww... Yo, try being a little less rough, haha. Anyway, I'll look for another way through. Later!”

He started walking back and froze at the statue. Coming towards him was Undyne, still in armor, although she wasn’t wearing her helmet.

“Y-yo!” he said, for the want of anything better. “Hey, U-undyne!” She kept walking until she was standing in front of him. MK quivered with fear and excitement as he looked into Undyne’s face. She looked… stern, but not angry, perhaps a little concerned.

“Hey, punk. Listen to me.” She sounded dead serious, like this was a matter of huge importance. “Go home and stay away from that human. He’s hurt a lot of people.”

“Y-yo, he’s a human?”

“Yeah. Now go home.”

MK found he could move again and started running, then fell. Undyne moved to help him up, but he struggled upright on his own and kept going. He wanted to find the monster - human - and ask him if he really hurt anyone.

He didn’t notice Undyne’s worried face as she watched him run in the direction of Hotland, not Snowdin Forest, nor did he hear when she started following behind him.

MK wandered Waterfall a little, trying to find the human again. He walked through a place with lots of mushrooms. He would have run, but every so often he had to touch the mushrooms so they would keep shining light around him, and if he stopped suddenly while running, he’d fall. When he’d passed that way, he ran through a long room filled with echo flowers. Then he turned a corner, and there was the human!

“Yo!” he cried. “Yo. Undyne told me to stay away from you. She said you... You hurt a lot of people. ... But, yo, that's not true, right!? …” The human turned away from him, an unusual expression on his face. “... yo... Why won't you answer me? A... a... and what's with that weird expression...?” He stepped toward MK, and MK stepped backwards. “Oh... Oh man... Man, my h-heart's pounding right out of my chest… ... what would Undyne do?” he wondered out loud. Undyne would stop him. Undyne would give her life to protect monsters. He made up his mind. “... Yo... Y-you'd b-better st-stop r-right where you are... Cause if you w-wanna hurt anyone else... you're... You're gonna have to get through me, first. A... an... and…”

The human took another step forward and raised his arm above his head. MK noticed for the first time that he was holding a toy knife, which looked surprisingly deadly in his hand. Then the human stabbed at MK.

A blur of shining metal landed between them, and a screech of plastic on metal sounded as the human’s weapon connected, not with MK, but with Undyne. A cloud of dust erupted around them.

Undyne doubled over, breathing uneven. Her hands clutched at her chest where she had been hit. For a split second, MK was excited and extremely relieved to see his hero, as well as surprised that he was not dead. Then it sank in that the stab intended for him had landed on Undyne. She didn’t look very good at all.

“Undyne… You’re… You’re hurt…” MK said with disbelief.

“Hurt? It's nothing.” she said, but he could tell it was more than nothing. “Next time, listen when I tell you to leave, okay?”

“Undyne... I…”

“I'll take care of this! Get out of here!”

If Undyne said she could take care of the human, she could, wounded or not. MK started back the way he had come. All at once, a new thought occurred to him, so sudden that he stopped in his tracks and fell. He picked himself up and turned around. He had realized that Undyne was going to beat up a bad guy, and he could have front-row seats to it, so he snuck back. After all, he would be fine. Undyne had said she would take care of it, right? Neither Undyne nor the human noticed him.

“...heh…” Undyne was saying. She looked in pretty bad shape. “‘It's nothing’... No... s-somehow, with just one hit… I'm already… Already… Papyrus... Alphys... Asgore… Just like that, I… I've failed you. No… My body... It feels like it's splitting apart. Like any instant... I'll scatter into a million pieces.” 

MK sucked in his breath. Was Undyne really about to die? 

“But…” she continued. “Deep, deep in my soul. There's a burning feeling I can't describe. A burning feeling that WON'T let me die. This isn't just about monsters anymore, is it? If you get past me, you'll… You'll destroy them all, won't you? Monsters... Humans... Everyone…” Everyone? The human would kill his own kind? “Everyone's hopes. Everyone's dreams. Vanquished in an instant. But I WON'T let you do that. Right now, everyone in the world… I can feel their hearts beating as one. And we all have ONE goal. To defeat YOU. Human. No, WHATEVER you are. For the sake of the whole world… I, UNDYNE, will strike you down! You're gonna have to try a little harder than THAT.”

MK watched, mouth hanging open, as Undyne changed before his eyes. He hadn’t noticed earlier, but her eyepatch must have fallen off. Every so often, in the space where her missing eye had once been, a light in the shape of a spear shone for everyone to see. Her hair ended in three points now, and her armor had changed, too. She attacked him with spears and more spears. 

Undyne was a hero now, dying but now at full health, fighting the human to protect every living monster in the Underground and to avenge every dead monster’s death. She was Undyne the Undying.

But even with all the spears, the human was only defending himself with an old tutu. Although it was old, it was definitely still strong, for few spears hurt him. Undyne paused, breathing heavily. The human kicked out at her right in the middle of the heart on her breastplate three times, and there was a crunching sound. She didn’t fall, but MK knew she was hurt. The human ate one of those nice creams that a monster kept trying to sell at Snowdin.

After a moment, she renewed her attack as though the fate of the whole Underground would be decided by this battle. This time Undyne hit him many times before she paused. The human retaliated, and they kept fighting for some time. Finally, he ate a piece of snow and kicked her three times in the same place. She fell then, nearly falling off the bridge.

Monster Kid almost screamed at the sight, but he held his tongue. He knew Undyne was doing this to save him; the least he could do was to stay safe.

She looked determined, even now, and was smiling as if nothing was wrong. “So even THAT power... It wasn't enough...?” she asked, starting to laugh despite her mortal wounds. “Heh… Heheheh… If you… If you think I'm gonna give up hope, you're wrong. Cause I've... Got my friends behind me. Alphys told me that she would watch me fight you… And if anything went wrong, she would... evacuate everyone. By now she's called Asgore and told him to absorb the 6 human SOULs. And with that power… This world will live on...!” She collapsed to the ground and closed her eyes.

The human laughed contemptuously. “That old turtle said there would be a hero to strike me down. Looks like he was wrong.” He walked away from dying Undyne, hardly glancing at her, and moved on, across the bridge and into a cave.

MK rushed forward. Her body was wavering a little now. 

“U-undyne?” he asked. She opened her eyes.

“Why are you here…? You’re supposed to… to be in Snowdin Forest.”

“Undyne... you saved me...? Yo, I thought I was a goner, haha... Yo, it looks like he kicked you pretty hard... Th-this is my fault. I should have stayed away from him, like you said.”

He heard footsteps from the direction the human had gone.

Undyne gritted her teeth. “Listen… You must shatter… my soul or absorb it… Don’t let him get it.”

Her body started to waver and lose its shape.

“N-no! U-undyne…!” he cried. MK grabbed one of her gloved hands in his teeth, touching his hero for the first time - her picking up him by the face didn’t count.

“Do… it.” she grunted. Suddenly, he found he wasn’t biting her hand, but a glove filled with dust. Before his eyes, she scattered into a million pieces. Monster Kid coughed as he inhaled some of it.

Then he saw it. A silvery soul shimmered above Undyne’s remains. How was he to get it without arms? The footsteps came closer. MK’s tail whipped out and curled around the soul, bringing it to his chest.

In a moment, it was gone, inside his little armless body. And the footsteps were still coming. MK whirled around to head back into Waterfall. He turned back, eyes glued to the dust and armor in front of him. He wanted something to remember Undyne by. His tail whipped out again and grabbed her gloves. He unglued his eyes from Undyne’s remains, got a glimpse of the human, standing mere paces away, and ran back the way he had come. The human ran after him, feet slapping on the ground. MK ran for his life, tripping here and there. He ran past the light mushrooms without stopping to turn them on. He remembered the path well enough, he decided. Behind him, they turned on, sometimes only a few seconds after he passed them, sometimes many seconds later.

Somehow the human didn’t catch him, and MK kept running. How long had he been running? What time was it? It was probably morning by now. He had long since transferred the gloves to his mouth so they wouldn’t slip from his tail in his flight.

He ran through a place he hadn’t been through before and stopped. The road ended abruptly, and there was a gap of water between the road on the other side. It was too wide to jump. There was a little bird standing on this side of the water.

It offered to give him a ride, and MK accepted without hesitation. The bird grabbed him in its talons and flew across with surprising ease, then carefully set him back down.

The human appeared on the other side, out of breath and angry that a monster had escaped him. MK didn’t stop to take advantage of the distance between them. He kept running. He dashed through the grass where Undyne had grabbed him by the face and pulled him out to look at him. Now he knew she had really been looking for the human.

He slowed a little on a bridge that looked like the builder didn’t know the meaning of the word “straight”. MK was breathing heavily, hoping he had given the human the slip and that he wasn’t following behind.

At the end of the bridge he turned, hearing faint footsteps. The human was still following, though MK didn’t know how. So Monster Kid kept running, leaving the bridge behind, passing both telescope and echo flowers without a thought but that he escape.

He ran on strange flowers opened in the water, across a bridge, and over more flowers. Then came more grass, the river with falling rocks, and the box. At the lookout post there was a skeleton. MK couldn’t decide if he was a child or an adult.

“ **looks like you could use a shortcut, kid,** ” he said, eyeing the fast-approaching human. He ambled out from behind his post and stood in front of MK. “come on.” He seemed in no hurry to flee from the human. They walked a few steps, the human getting ever nearer.

Then they stood in front of Monster Kid’s house. The skeleton turned to MK. “how was that for a shortcut?” he asked. “don’t worry, kid. i’ll keep an eye socket on him.” He turned, walked a few steps, and disappeared.

**Notes for the Chapter:**

> I know there could be more description about the Undyne battle and MK's flight, but I'm writing the story from his perspective, and especially during his flight he wouldn't have time to notice many details.
> 
> The other chapters should be posted shortly. It mostly depends on when I get around to doing a final edit on the next chapter to be published.
> 
> EDIT: The human now tries to kill MK with the Toy Knife instead of Ballet Shoes to make it canonical to [When Undyne Called](https://archiveofourown.org/works/22091332).


	2. Leaving Home Again

**Notes for the Chapter:**

> This is still mainly the original content with random minor edits. The only "major" edit is the addition of the school fight scene. I also added a few things into the Undyne the Undying fight scene in the previous chapter.

The door flew open to reveal his mom. She must have seen him through the window. “Monster Kid!” she cried. “Where have you been? We’ve been worried sick about you!” She sounded much more worried than angry, but the anger made its presence known more and more as her worry level dropped. “Get inside and stay there!”

Understandably, MK’s legs felt wobbly. He walked inside and into his room. As he laid the gloves - Undyne’s gloves - on the nightstand in his room, he heard his mom on the phone.

“Yeah, he just came home. No, MK just appeared in front of the house with a skeleton, and then he disappeared. No, not MK, the skeleton. Alright, see you soon. Be careful!” *Click.* Mom entered his bedroom and turned to MK, eyes on fire with anger and concern. “We’ve been worried sick about you! Where have you been? Dad has been all over the forest looking for you. He should be home any minute, and then we will have a long talk. Until then, stay in your room.” She left, shutting the door firmly behind her.

“Yo, how do I explain this?” MK muttered. “Mom’s not gonna believe any of this.”

For the first time since Undyne had died he had time to think about everything that had happened. He felt like he had more magic than before, and it was stronger, too. A warm sense of reassurance came from his chest. As long as her soul was in one piece, Undyne was alive and lived on, if only in an armless kid’s chest.

You’ll do fine. Monster Kid jumped as Undyne spoke in his mind.

“Undyne?”

Yeah, I’m here. As long as you’ve got my soul, I can talk to you.

“Yo, that’s cool.” His eyes widened as he fully understood the fact that Undyne basically lived inside him now. Suddenly, he started running circles in the middle of his room for lack of a better way to express his excitement. It was also somewhat scary knowing that his idol and hero existed only because of him.

The front door opened, and MK heard Dad come in. Then Mom opened his room door. He silently walked out. Mom and Dad sat on the couch in the living room, and MK took the rocking chair.

“Alright, MK,” Dad said, “Explain yourself.”

MK twiddled his toes, his face nervous and uncertain. His tail twitched.

“Uhhh… I w-wanted to see Undyne. A-and since I’m going to be an adult soon I th-thought it was my only chance to s-see her ’cause when I’m an adult I w-will be staying home and I won’t be able to s-see her.”

You’re doing fine, punk.

MK’s lips twitched into a half-smile.

“What are you smiling at, MK?” Mom demanded sternly. “This isn’t a funny matter.”

“S-sorry.” The smile disappeared, but not the reassurance Undyne had given him.

Frowning, Dad clarified. “So you snuck out of Snowdin Forest, which we have repeatedly told you not to do, and tried to find the Head of the Royal Guard?”

“Y-yeah.”

“And did you find her?”

“Yeah.” He smiled a little now, remembering the feeling of when Undyne grabbed his face and lifted him out of the grass. It left when he thought about what had happened with the human, but returned with Undyne’s words.

I was just doing my duty. Don’t worry about it. You were ready to do the same. That was true. He had tried to be like her then, knowing that he was signing his own death warrant.

“Did she say anything?” Mom asked.

MK nodded.

“What?”

His mouth curved downward again, this time in concentration. Undyne had said a lot, and he didn’t know how to answer. “Uhh, she said, dude, don’t go near the human.”

“The human?” Mom inquired worriedly. If she hadn’t been completely alert before, she was now. “Did you see him?”

“Yeah.” MK hung his head. He knew full well what his actions had cost the whole Underground.

Dad asked, “What happened?”

“H-he tried to kill me, but U-undyne… Undyne jumped in front of me and… and got hit instead. A-and then they fought. Yo, she was so cool!”

“And then?” Mom asked, feeling a sense of dread she hadn’t felt before.

“She was r-really determined, b-but… but the human k-killed her.”

Silence. Mom looked at MK in disbelief, but Dad just stared at nothing as if he was in shock.

Finally, he spoke. “How did you get home? Did the human see you go into the forest?”

“W-well, he chased me in Waterfall b-but there was this bird that helped me. And then the human found me a-and chased me some more but a s-skeleton took me on a shortcut a-and then I was home.”

More silence. MK sniffled. He knew he had Undyne’s soul, but her body was gone forever. Now there was no Head of the Royal Guard, and the human was going to try to kill everyone. In one sense, Undyne was alive, but in another sense, she was dead, and she would never return to protect the monsters.

A tear trickled down his cheek. MK slid off the recliner and ran to his room, shutting the door behind him.

It’s alright, kid. I would have fought him whether you were there or not.

_Thanks, Undyne,_ MK thought. He sniffled again and walked over to the gloves, still full of Undyne’s dust.

He breathed in the dust and the smell of his hero. It smelled like fish and burnt spaghetti. If determination had a smell, this was it. He tried to wrap his tail around them, but they fell, hitting him and landing on the floor. The dust spilled all over him, but MK didn’t mind. After all, it was some of the remnants of his hero. He opened a drawer, successfully grabbed the gloves with his tail, placed the gloves in the drawer, and shut it.

Then he sat on the bed. There was a lot to think about. Even though he wasn’t an adult, he understood that what had happened could never be undone. More than that, he knew that having Undyne’s soul along with his own in his body meant that he was probably the most powerful monster in the Underground. Well, second most powerful. Before she died, Undyne said that Asgore would absorb the human souls, and a single human soul was the equivalent of all the monster souls in the Underground.

After a while, the silvery dust was gone. MK stood and walked out of his room.

Mom was sweeping the floor. At her feet was his sister, Monster Girl, or MG for short. “Huh. You look like you’ve matured halfway to adulthood, MK,” Mom commented with little emotion. Maybe he had. A lot had happened in the space of one night. She fell silent, still needing to process what her son had told her about his foolish adventure and near-death escape.

She didn’t say anything about school, so he assumed it was canceled. There had been an urgent announcement on TV by Mettaton that Undyne had died and that all who could without endangering themselves should go to the Lab, where Alphys would accommodate them and keep them safe. MK’s family wasn’t going because they had young children, the forest had yet to be explored by the human, and they could run into the human on their way there. Everyone knew that Undyne had fallen. No, not fallen, died. To fall down was to become comatose, and she was dead, her dust scattered on and below a small bridge before the entrance to Hotland.

From what MK overheard, the human had last been seen in Hotland by monsters who had been taking their time evacuating.

Mom didn’t let him out of the house that day or the next. Whenever she did let him out of the house, it was only under supervision or with the promise that he would stay within sight of the house. She was reluctant to let him go to school, but Dad intervened, saying that it would do MK some good to have something to do, even if the things he learned would be useless once the human snuck into the forest and killed them all.

It was a week before Mom gave in and allowed him to return to school. The first thing MK noticed was how everyone looked at him, and none of the looks they gave, save one or two half-sympathetic glances, were in any way condoling. Everybody knew who was responsible for Undyne’s death. To MK, it implied that everyone wished that he had died instead of her.

By the second class, MK had been called more names and had been insulted more times than during the rest of the semester combined. The nicest of them were “stupid,” “idiot,” and “That was the dumbest thing in the world.” If he hadn’t had Undyne with him, he would have run home in an instant. Because of her support, he managed to not only get through the school day, but also to not fight anyone except Jerry, who was just too much for MK to remain passive.

It was not the best of ideas, as some of the nearby monsters jumped in, glad to have a reason to lash out at him.

The teachers broke it up quickly, scolding the perpetrators - MK most of all - and threatening to call their parents.

Neither of MK’s parents were happy to hear of the fight, both of them unnecessarily reminding him that if he had brought it on himself. Still, they loved him, and they were definitely glad that he was alive and well.

School was canceled more than usual, now that Undyne was gone. When that happened, Mom taught him at home or made him help around the house.

“You’re getting tall,” she would say, “You might even be the tallest of our kind when you’re fully grown. Since you’re so tall, help me dust this high shelf.” or “reach up there and get me such and such an item.” or “take down the stuff in that cabinet so we can sort it.”

Even with all the work, Monster Kid always found some time in the day when he could be alone and talk to Undyne. They talked every day and started becoming friends.

 _Yo, Undyne,_ he asked one day, _What’s it like inside me?_

It’s like being able to do everything you can except move and talk.

_Are you lonely?_

Nah. Then she reconsidered. Well, a little, but I’ve got you.

Undyne was of little help in his schooling, saying that she was never interested in books and stuffy old teachers, no offense to the teachers. She had always been more into the hero stuff, beating up bad guys - or the mailmen - and saving the world. In the end, she had settled for being Head of the Royal Guard. She hadn’t actually beat up any bad guys or saved the world, but she had been a hero who gave her life for a foolish armless kid whose parents had no idea what he was up to.

As the weeks passed, MK grew more restless. Dad gave him a cell phone so he and Mom would always be able to reach him. But MK didn’t want to stay at home. He wanted to join the Royal Guard. After all, Undyne was still his hero, and he wanted to imitate her.

Mom wouldn’t let him.

Dad wouldn’t let him.

MG was too young to care.

And MK was filled with determination.

It had been two months since Undyne died. MK couldn’t stand it any longer. Undyne’s retellings of Gerson’s tales and exciting stories about training made him wish he was there. She wasn’t any help, often muttering that the human would kill everyone or that there was no one to stop him.

One night, his parents were asleep. MK wasn't. He was fully awake, and he doubted he would fall asleep anytime soon. MK sat up silently, resting his chin on his knees. Undyne’s action-packed adventures were playing in his mind, and Undyne herself was hinting that he could go see Asgore to be in the Royal Guard. It sounded like a great idea to MK. Undyne was with him, so nothing bad would happen, and even if something did happen, Undyne would help him.

He swung his feet over the edge of the bed. Undyne continued to encourage him to go to Asgore. He stood on the hardwood floor, carefully walking so that his nails wouldn’t click, which would probably wake his parents. Undyne kept enthusiastically spurring him onward.

Before he left the house, MK scribbled a short note and left it on the dining room table, where his parents were sure to find it in the morning. It read simply:

_Mom and Dad,_

_I went to join the Royal Guard. Don’t worry, I’ve got Undyne with me._

_MK_

He didn’t care if his parents didn’t know what he meant by having Undyne with him, but maybe it would reassure them… and convince them to not attempt to traverse the majority of the Underground to bring him back home.

This time he wasn’t running willy-nilly through Waterfall. Undyne knew this place like the back of her soul. MK didn’t run as much now. A while back, he had discovered that he could walk at a fast pace without falling nearly as much as if he ran.

MK reached the place where Undyne had died, and he stopped for a moment, reliving that night and looking back the way he had come. It wasn’t too late to turn back.

Don’t wimp out, punk.

“I won’t, Undyne.”

He crossed the bridge Undyne had died on, noting that her armor was gone, and walked through the cave that marked the entrance to Hotland, now relying solely on his hero and friend to guide him through Hotland. He took a drink from a water cooler.

Now there was a crossroads: an elevator to the left, the boat to the right, or the Lab straight ahead.

_Which way, Undyne?_

She was strangely silent. After a long time, she replied.

Do me a favor and stop in the Lab for a little, ok? Alphys lives here.

MK walked to the Lab door. It was locked. He knocked on - banged his head against - it. No reply. He tried again. The third time, someone shuffled to the other side.

“W-who is it? Are you f-friend or foe?”

“Friend.”

The door unlocked and slid open. On the other side of the door was a yellow monster wearing glasses and a lab coat. She reminded MK of his family.

“Ummm… H-h-hiya!” she said, looking very nervous. “I'm Dr. Alphys. I'm Asgore's royal scientist! C-come in!”

When they were both inside and the door safely locked again, Alphys looked at him more closely.

“Oh! You’re the monster U-undyne… Undyne d-d- saved.”

“Yeah.”

“S-so why- what do you need?”

“Um, Undyne wanted me to stop here.”

“U-u-undyne w-wanted you to? B-but I- I thought… I thought she died.”

“She did, but… I have her soul.”

“W-w-what? Y-you have her s-soul?”

“Yeah.”

“Oh! Th-that’s cool! At least, I think it’s cool. I’ve never had another soul so I don’t know.” She laughed uncertainly.

MK stayed in Alphys’ lab for the rest of the day, explaining and letting her run tests on his and Undyne’s souls. They also watched a little anime. MK didn’t know what to think of it, but he could tell Undyne was really enjoying it.

Alphys offered to let him sleep in her bed, but he said he was fine sleeping on the floor.

MK didn’t leave the Lab for another week. Alphys told him that she had gotten a great idea and was going to make him arms. He suspected that she also wanted to stay around Undyne’s soul and watch anime with someone.

But nonetheless, Alphys did create arms for him. MK never understood how she made them to function with his body, but they did work. She even painted them the same color as his body. It was a new sensation to have arms and hands. No more opening doors or carrying things with his mouth. At home, all the doors had been specially designed for teeth or tail, since nobody had hands to turn doorknobs.

The next day MK left the Lab with instructions on how to get through Hotland. It was really very simple. He took the left elevator up to the right side of level three and entered the MTT Resort. Inside, there was a fountain of Mettaton that didn’t seem to have been engineered properly. Very few monsters were there, none of them guests

Monster Kid had never been so far away from home! Before sneaking out to see Undyne, he had never been outside of Snowdin. Now he had passed Waterfall and Hotland and was entering the Core.

The Core looked like its decorator had been a big fan of blue. MK nervously walked on bridges with more lasers than he could count, but none of them turned on. Out of Waterfall, Hotland, and the Core, the Core was the easiest to find his way around in. It was small, and most of the time there was only one path to take.

In a short time, MK was out of the Core. He took the elevator at the end and rode it to whatever level Undyne said. When he stepped out and turned the corner, he saw New Home for the first time. It was magnificent, but more quiet than he would have expected.

Are you going to stare at it for the rest of the day or find Asgore and ask to be in the Royal Guard?

He shook his head to clear it. _I’m going, Undyne._ It felt strange to walk through Asgore’s house to find him, but Undyne assured him that she had done the exact same thing when she asked to be in the Royal Guard. MK descended the stairs and ran through the hallway, falling only once.

There was another view of New Home, but he ignored it. Now he just wanted to find Asgore before he “wimped out”, as Undyne put it. After that there was a long hallway with a checkerboard floor. Each of the large, almost-triangle windows had a Deltarune on it.

Another long hallway, and when it turned the corner MK saw a door on his left. Undyne didn’t need to tell him to go in. He walked in on legs like jelly that were only barely stable enough to walk on.

The middle of King Asgore’s throne room was covered in golden flowers. They must have been the ones Asriel had collapsed on years earlier after his failed journey to the surface. The rest of the room was almost completely covered in green leaves of some kind of plant. There was a throne in the middle of the golden flowers, and another covered up in the corner.

Asgore was bent over, watering the flowers.

“I’ll be with you in a minute,” he said, not turning around. When the flowers were watered, he set the watering can down, straightened, and turned to Monster Kid.

“What can I do for you?” he asked.

Now’s your chance, punk.

MK twiddled his new fingers nervously. “I, um, Mr. Dreemurr, can I… join the Royal Guard?”

Asgore hesitated. “Why don’t you see if you can fight me first?”

I tried to fight him when I asked to be in the Royal Guard, Undyne told MK. He dodged my blows and refused to hit back. I was so humiliated! But then he offered to train me.

“Yo, you’re just gonna dodge my attacks, like you did with Undyne, right?”

“How do you know I did that with Undyne?”

“S-she told me.”

“She told you? When?”

“J-just now. I-I have her soul, a-and we talk sometimes.”

Asgore looked at MK in disbelief. It reminded him of how Mom had looked at him when he told her Undyne died.

“You have her soul?”

“Yeah.”

The king was quiet for a long time.

“Fight me first so I can see if you are qualified,” he said finally. “It is a challenging job under any circumstance, even more so with the human around.”

MK was reluctant to fight. Then he stepped forward and tried to punch Asgore. For his size - and weight - the king dodged each blow with surprising ease.

After ten minutes of trying to hit Asgore with no success, MK stopped, breathing heavily.

“S-see,” he panted. “You just… dodge them… like with Undyne.”

“I do.”

MK looked at the floor, ready to turn around and go home the instant Asgore said no, he couldn’t join. But instead the king approached him.

“I’ll train you, if you want.”

The badly yet aptly named monster kid looked up. “Really?”

“Really.” Asgore smiled down at the maturing monster. “We can start today, in fact.”

YEAHHHH!!!!

MK giggled. “Undyne’s excited.”

**Notes for the Chapter:**

> There are some parts that are a little choppy or could have otherwise been made to sound better, but I am mostly just publishing this to get it where other Undertale fans can see it, and I don't feel like taking the trouble of making every part sound amazing.
> 
> EDIT: Added Mettaton's announcement that he promised to make in [When Undyne Called](https://archiveofourown.org/works/22091332).


	3. Evacuating Snowdin Forest

**Notes for the Chapter:**

> Again, nothing much has changed from the original, except a little wording, description, and adding Doge into the evacuation scene.

He started in the lowest ranks, with Asgore as his personal trainer, and he began by improving his speed. Other times Asgore taught him accuracy and helped him to get more familiar with magic and what he could do with it. They really had nothing better to do, unless they wanted to look for the human, and so almost all of nearly every day was spent in intense training sessions, if not with Asgore, then with other members of the Royal Guard. But even the King didn’t know or understand how Undyne’s soul could help him, so he would send MK to Alphys every so often for tests and such.

When he was over at Alphys’ lab, he knew to expect another episode or two of anime. He was actually starting to like it.

“Y-you know,” Alphys said one time, “Y-you really remind me of Undyne. I-I mean, you talk like her sometimes, a-and you’re really determined, too. I saw her last battle. She had so much determination that she m-melted a little before she died. M-monsters can’t handle as much determination as humans can. I learned that the hard way. Ha ha.” She paused. “B-but with two souls, I don’t know what effects that will have. M-maybe Undyne’s soul can store lots of determination w-without melting you.”

Undyne had a theory of her own. She thought that, if you were determined enough, you could use that determination to enhance the magic attacks and thus the determination wouldn’t melt you because it was constantly coming out in the magic while you kept getting filled with it. The theory held some weight, for Undyne was, after all, the only monster to melt at all but was still able to tell the tale, although only MK could hear it.

Asgore had absorbed the six souls when Undyne died, but the human had yet to show his face around the capital. It had been four months since he had tried to kill MK. Why wasn’t he trying to defeat Asgore? Maybe he was just waiting for a better time, but what better time than now? Alphys had evacuated almost all the Hotlands and Core monsters, although a few, like Muffet, were stubborn and refused to leave.

Monster Kid improved constantly, working his way through the ranks until he was among the top 5. More and more he resembled Undyne, speaking like her, looking like her in some ways, and his magical attacks were almost always spears, partly in memory of her, and partly because he found it easy to create spears.

MK hadn’t seen his family since he had left, but he had called them a few times with his phone, which Alphys had insisted on upgrading it for him. Mom was relieved to hear his voice and asked that he come home. Dad was also glad to hear him, but he was sterner than Mom had been. “Didn’t we tell you _not to leave like that?”_

“I’m sorry, Dad, I got restless and I really wanted to join the Royal Guard. But I’m in the top 5 now.”

Dad huffed into the phone. Then Mom took it back and commented on how much more mature he sounded. MK had noticed, too. He didn’t use words like “yo” any more.

It was nice to hear their voices, too. He missed them, but he couldn’t take a break and see them. He was in the Royal Guard, and they were always on call for any emergency. As he was in the top 5, Asgore relied on him greatly to help organize and lead the Guard with the other top 5 monsters.

Sometimes, even as high in the ranks as he was, MK wanted to quit. Whenever that happened, Undyne would help fill him with determination, reminding him that she hadn’t done that, and if he wanted to be like her, he couldn’t give up. Then he felt better and worked twice as hard at whatever he was being trained on.

Two more months, and Monster Kid was the Head of the Royal Guard. One of the other monsters he worked with jokingly nicknamed him “Undyne," remembering how she had risen through the ranks like he had. Although it was a girl’s name, the name Undyne stuck, and more often than not, he was called Undyne instead of MK.

Undyne didn’t mind. He had asked her, and she only said, Way to go, punk.

Only Asgore and Alphys knew he had Undyne’s soul, so he was surprised when one of the Royal Guard said it seemed that, in a sense, Undyne lived in MK.

That reminded him of something he had read a long time ago in the Librarby in Snowdin. It was a school report about monster funerals, and it read, “At funerals, we take that dust and spread it on that person’s favorite thing. Then their essence will live on in that thing…”

There hadn’t been a funeral for Undyne because things were too tense for people to care about a funeral, even if it was for the Head of the Royal Guard. But after he had her soul, MK had taken Undyne’s gloves home, still filled with her dust. The dust had spilled all over him some time after he had gotten home. Later, it had disappeared, and he assumed it dispersed into the air, but perhaps he had unconsciously absorbed it instead.

It would explain why he was so much taller than the rest of his kind and why he looked like her, especially when he was in armor. He wasn’t a boss monster, though. Only Asgore was a true boss monster. The queen and their son had been ones, too, but she had left New Home shortly after their son died and nobody had seen her since.

MK realized that technically Undyne’s soul shouldn’t have persisted after death at all, nor should he have been able to absorb it, but perhaps her determination caused it to be that way.

Six months had passed since Undyne’s death, and rumors were flying fast and thick. Most of the evacuated monsters had gone home, much to Alphys’ concern, and now some reported having seen the human. More than one monster had gone somewhere alone and never returned.

Then he was sighted. Mom called MK one day, frantic as a bird being chased by a cat. “MK! I saw the human!”

“In the forest?”

“Yes! What are we going to do?”

MK felt panicky too. “I don’t know. Go somewhere safe - anywhere. Get to Hotlands and into Alphys’ Lab or the MTT Resort. Go to the Ruins and see if you can get inside.”

“You’re in the Royal Guard! Can’t you come and protect us?”

 _Did you see what he did to Undyne?_ MK thought. _And shouldn’t I get Asgore’s permission first?_ But no, this was too important to wait for Asgore’s permission. He was the Head of the Royal Guard; Asgore trusted his judgement. “Yeah, Mom, I’ll come as fast as I can.” The king was busy, so MK left a note with one of the Royal Guards in the barracks:

_The human was spotted in Snowdin Forest. Went to evacuate the monsters to somewhere safe. Took Doge with me._  
_Undyne_

Doge was the only living member of the Snowdin Canine Unit. She had been away when the human had come through Snowdin, so she was not massacred like her friends and family. Out of the rest of the Royal Guard, she was probably the most familiar with the snowy land.

Asgore would know that Undyne was MK. In fact, he was hardly called MK anymore by any of the Royal Guard, Asgore, or Alphys.

He had heard that Mettaton lived near or with Alphys, but so far he hadn’t seen him live on TV. He was probably trying to film another movie. The last one - METTATON THE MOVIE XXVIII - was pretty awful according to MK. Most of it was four hours of rose petals being continually showered on Mettaton as he did nothing but recline in the spot where MK had first seen New Home. In fact, most of his movies were like that. MK suspected that he was just rereleasing the same movie or movies over and over.

Right now Mettaton didn’t matter at all, unless he was among the residents of Snowdin Forest, which MK highly doubted.

He wished that the skeleton was here now. His “shortcut” had most definitely saved MK’s life when he was being chased by the human. Another “shortcut” would be very convenient to get him to the forest faster.

But he had no teleportation powers that he knew of, and so he’d have to go the usual way. Now, more than ever, he was grateful to Alphys for fashioning him arms. MK could run all he wanted and wouldn’t fall on his face _nearly_ as much as before.

By now he knew his way around the Underground as well as Undyne, or nearly as well. His armor clanked as he ran, and he didn’t care. Monster lives were in danger, and he, as the Head of the Royal Guard, had the duty of protecting monsterkind at any cost. Undyne had given her life for him, one armless monster among so many. The least he could do was to try to live up to the honor of her name bestowed on him.

Through the Core, across the MTT Resort. Into Hotlands, turn left, down the elevator. Now Waterfall, the bridge where Undyne died, and the light mushrooms. Ignore the Temmie village; they’re not in danger. Turn at Gerson’s shop and take the boat to Snowdin. Leave the boat, pass Grillby’s and enter the woods. Most of the monsters lived in the west part of the forest.

Here there were paths and paths, some dead ends, others looping so long you got lost, some seeming to have neither start nor end but appearing and disappearing in the middle of nowhere. MK and Doge ran through them like only those who had lived in Snowdin Forest could. As he ran toward his home, he tried to decide where to take them. He remembered a place not far from the forest, a strange door he had never opened.

But now he knew how to open it. MK had seen a similar one in New Home, and Asgore had shown him how it worked. Each of the six symbols making up the Deltarune were buttons, and if you pressed them in the right order, it would open.

Now he was home. He knocked, and the door swung open. Mom stood there, looking up at him.

“MK? You’ve really grown! And how did you get arms?”

“Later, Mom.” he said, ducking as he stepped inside. “The human’s around, right?” Having received no orders to come in, Doge waited outside.

“Yeah,” Mom affirmed. “Everybody’s been waiting for you. They’re ready to move when you say the word.”

“Good.” MK ran to his old room. Evidently nothing had been disturbed. He opened a drawer and pulled out Undyne’s gloves, which he had been wanting for some time.

They were a perfect fit. He left his room and found his parents and little sister ready and waiting.

“Let’s go.”

The monsters were more than ready to follow MK with Doge as a rearguard. He seriously doubted that they would have followed him six months earlier, but times had changed and his Royal Guard armor made them feel safer.

As they hurried through the forest, he learned that the human had been spotted in the east side of Snowdin Forest. Good. If he knew anything, he knew that that human wouldn’t be able to find his way through it for a long time. It was filled with holes, and in some places the trees were so thick they seemed like one huge tree and you had to detour around them. That was why few monsters had lived there, and those who once made their residence there had fled at the first sight of the human.

MK led them out of the forest near the “Welcome to Snowdin Town” sign. They had to walk single file on the bridge, which creaked from the weight of so many monsters. But they made it across, passing Doggo’s old home and many snow poffs. When he turned and started down to the door, the monsters who knew where he was going started getting more nervous.

“There’s no way out!”

“You’re just leading us to a dead end!”

“We’d do better to try to get the Ruins door open! At least there’s more forest there!”

Some even tried to turn back, but at a glance from MK, Doge stopped them.

“I know what I’m doing. You may keep going alone if you’d like,” he finally said. That was enough to silence them. No monster wanted to continue to the Ruins door without MK.

The monsters were packed inside the cave with the door. Now everyone was worried and talking in “quiet” voices. He ignored them and concentrated on the door. It looked no different from the one in New Home. He reached up and pressed the buttons. Left wing, middle triangle, right wing, left triangle, circle, right triangle. The door opened inward without a sound, and some monsters were so busy getting nervous that they didn’t notice it at first.

MK walked in and held the door as the monsters rushed inside. On the other side was a tunnel, which led into a calm place he had never seen before. Trees grew in some parts and winter flowers in other places. Snow covered the ground. Some bushes held red berries, and a couple dogs started sniffing out roots and nuts underneath the snow.

“How did you know…? When have you been here?” Dad sputtered.

“I’ve never been inside. Asgore showed me a door like this one in New Home and how to open it. That reminded me of this one. If that door opens by pressing the Deltarune symbols in the right order, I thought this one would, too.”

Monsters on all sides were congratulating MK and thanking him for bringing them to this place. Doge stood vigilantly at the closed door.

“You’ve grown so much! How’d you get that tall?” an aunt asked MK. It was true. He was easily the tallest of his kind by at least a head.

“And how you’ve matured! I haven’t seen you since last year, and all you jabbered about then was Undyne!” exclaimed an uncle.

“How’s it like in the Royal Guard?” his grandfather asked. “I served on it around the time Undyne joined. ’Fact, I even saw her knock down Asgore for the first time. She looked so embarrassed, but he was beaming like the barrier had broken!”

“It’s great!” MK replied. “Somebody called me Undyne one day and it stuck. Now everybody calls me Undyne there.”

“I remember Undyne when she was just a little fry. She was the cutest thing, and if you saw her then you could hardly imagine that she would be Head of the Royal Guard!” said his grandmother. “It’s a shame she died. No monster could replace her.” MK turned away so that she wouldn’t see his red face. As far as he knew, she was one of the few who did not know that he was the reason Undyne had died.

MK knew Undyne was getting embarrassed. Ahhh, anyone could replace me. You have.

_Not really. They call me that because I remind them of you, not because I replaced you._

Everyone was safe in this strange new place he had opened for them. The door locked automatically when it shut. Only those who knew the code could open it from the outside, but on the inside you could open it without a problem. There was a bar on the door and MK lowered it, providing extra security to the monsters on this side.

This place was mysterious. He had never seen it before, and it was a spacious haven for the monsters of Snowdin. They could even make a new Snowdin Town, although it would be larger and more cramped than the current one. That reminded him. The monsters had been hurrying so much that nobody had bothered to cover tracks, unless Doge had taken care of it.

MK needed to go. Everyone would be safe here - there was food and shelter for all. He’d come back and check on them often.

This time, though, he said goodbye to his family, ordering them to place the bar when he left. He walked out with some branches and started smoothing out the snow behind his footprints. There were none leading to the evacuated monsters, so Doge must have remembered what MK had not. Evidently, the human hadn’t passed this way yet. He glanced up toward the peak of the cavern. It looked like a storm was brewing. Good. It would wipe away any remaining traces of the monsters’ evacuation.

MK passed through the forest, covering his tracks as he walked. Everyone was safe. When the human showed his face, he would settle everything once and for all. He looked at the now-empty houses, and they filled him with determination.

Once he was out of Snowdin, he tossed the branches into the water and watched them float away.

The skeleton was in his lookout post again.

“ **heya. i’m sans. sans the skeleton.** ” He held out his hand for a shake.

“I’m MK.” He took the hand and started as a strange, embarrassing noise came from between the hands.

“ **heheh… the old whoopee cushion in the hand trick,** ” Sans laughed. “ **it’s ALWAYS funny.** ”

MK laughed at the joke played on him, and then turned serious again. “You need to go somewhere safe,” he said. “I’ve already evacuated the monsters of Snowdin Forest. I can take you there to them.”

“ **Nah, I’m fine. Just keeping an eyesocket out for the kid. Hasn’t passed this way recently.** ” Something in him assured MK that he was more than capable of taking care of himself.

“Alright. Tell me if he does.” He turned to leave, but stopped. “And Sans? Thank you for saving me.”

“ **no prob. couldn’t let him get someone as special as you. all in a day’s work.** ”

As special as you. Did Sans know he had Undyne’s soul? He thought only two others knew that besides him.

He left then, hurrying back to New Home. Asgore would want to see him and might ask for a report on what he had done. Besides, with all the weaker monsters out of the way - except for a few stubborn ones here and there - the human would have to show his face unless he fancied wandering Snowdin Forest for a few more months. By now he was probably sick of the crazy paths that covered the snow.

Asgore was waiting for MK. “Make your report, Undyne.”

“Doge and I moved them all to a safe place. In a cave between the Ruins and Snowdin Town there’s a door with buttons making up the Deltarune symbol. It opens like the door you showed me. Inside there’s a tunnel opening into a place with plenty of food and shelter. Also I talked to Sans the Skeleton. Said he was watching for the human.”

“Good work, Undyne. Did you see the human?”

“No.”

**Notes for the Chapter:**

> I know, the mysterious door in Snowdin doesn't actually open into the place described in this chapter. My excuse is that it will only open in-game if you dodge all the credits after a TRUE PACIFIST route, and "the human" is certainly not a pacifist in any way. Maybe the mysterious door leads to a different place depending on who is trying to open it or what Frisk does in the Underground.


	4. The Human

Things were quiet for a week, but that didn’t mean that the tension was gone. Nobody had forgotten that there was a human traversing the Underground. It was only a matter of time before he would show up in New Home.

MK was wandering New Home before anyone else was awake. He wanted to think about what might be ahead for him. As Head of the Royal Guard, he had to be prepared to die for Asgore, more so than one of the regular rank-and-file guards. Lately he had been remembering what Undyne had done to save him, and was filling him with determination.

Sans appeared in front of him. MK halted in his tracks, unable to read his expression but certain it meant the human was up to no good.

“ **heya,** ” he greeted, breaking the silence but not the tension. “ **kid’s in waterfall, coming this way.** ”

“Thanks.”

Then he was gone and MK was left standing in a silent street. His mind automatically switched to plans and tactics instead of Undyne dying for him. This time, he felt it would be best to hunt the human down instead of waiting passively until he appeared in the Throne Room, having killed every monster he had found in Hotland and the Core.

If that was the plan, there was no time to lose. The longer they waited, the more lives they were putting in danger. MK roused the Royal Guard and Asgore, telling them what Sans said and outlining his plans. Asgore agreed quickly, and that was that.

The Royal Guard was ready. They especially wanted vengeance on the human for killing their friends in the Snowdin canine unit of the Royal Guard. But everyone agreed that it should be MK or Asgore who fought - as they were the strongest two, MK with Undyne’s soul and Asgore with the human souls - and the rest of the guards would only help if they were needed.

MK left his helmet behind, wanting to feel the cool air of Waterfall directly on his face. Besides, the armor burned in Hotland, and wearing his helmet on top of that was nearly unbearable. Mature or not, he was nervous. Most of the fighting he had done was against Asgore, and never against the human.

Calm down, MK, Undyne told him, Either you kill him or you die trying.

They were leaving now. They would leave some of the Royal Guard in Alphys’ lab to provide an extra measure of safety to the monsters temporarily quartered there, as the monsters she had evacuated were apparently all living in her lab. It must have been a bigger lab than MK realized.

As long as they were safe, that was good.

Hotland took some time to get through, mostly because the elevator couldn’t hold everyone at once. Since Hotland didn’t have paths designed for most of the Royal Guard to pass through, they all had to use the one elevator, which made it take longer than any of them would have liked. Asgore alone was large enough to take up all the space in the elevator. They started at R3 and travelled to L1. Those who had already taken the elevator waited and regrouped in Alphys’ lab, where it was air-conditioned.

After leaving a few guards in the lab, they left Hotland and entered Waterfall. Everyone was silent and edgy. Per Asgore’s command, they split into two search parties, headed by MK and Asgore. MK wasn’t terribly pleased with the idea, but he wasn’t about to talk back to Asgore in a time like this.

Undyne wasn’t happy with it either. She was talking to herself, but her words echoed MK’s own thoughts. _He’ll_ find the human, and when he needs us, we won’t be there.

MK took his party and separated from the rest. They were going to start at the border of Snowdin and Waterfall and systematically move through Waterfall until they either found the human or met up with Asgore again.

They had explored most of Waterfall when MK decided to head back to the entrance to Hotland. He hadn’t seen any signs of Asgore’s party, which meant that they had almost certainly found the human. Near the entrance to Hotland, MK heard sounds of battle. His suspicions had been correct.

He ran ahead of his group and saw a terrible scene: many of the Royal Guard lay on the ground - either wounded, fallen, or dust - near the two combatants on the bridge where Undyne had died. The human seemed no worse for wear, but Asgore was hurt in multiple places.

Then he was down on the ground, helpless, as the human lifted an old pan over his head, preparing to smash Asgore’s head.

MK was already moving. He jumped between them, ignoring the human and pushing Asgore to the other side of the bridge while shielding him with his body.

The pan crashed into his back at full force, and he staggered, crumpling to the ground. It was a fatal blow; he was sure of that. He turned his head to face the human, who was watching him now, waiting for him to crumble to dust so he could get past and finish Asgore off.

Undyne couldn’t accept the idea that MK was dying. No… No. No! This is NOT happening. If Asgore had been about to die, and it had only taken one hit to fatally wound MK, nothing could stop the human.

The human started cautiously towards MK, deciding that he couldn’t make the same mistake he had made with Undyne.

A wall of hammers appeared between them. “Woah there, kid!” a voice called down from above. They both looked up to see Gerson on a ledge above them. “Let the hero die in peace.” The human turned around, but before he could approach the other monsters, another wall of hammers stopped him. “Slow down, human. Take a little break from fightin’, maybe.”

The human glared at Gerson, who laughed. “Eh? You wanna fight me? Tough luck, I’m up here and you’re not. B’sides, one attack from you and these old bones would go down. I’m not a hero.”

The human spoke. “Hey, that reminds me,” he said, tone almost conversational. “You said there would be a hero to strike me down, but the strongest monsters are dying. Looks like you were wrong.”

MK started talking. “In one hit, I’m already… already dying?” he asked. It was hard to believe that he had been killed that easily.

But the simple knowledge that he was about to die filled MK with determination, and the pain in his back lessened as little sparks of something started burning inside him. He remembered what Undyne had said in the same place when he thought she was dying. “But in our souls… There’s that burning feeling. The feeling of determination. Undyne was right,” he mused, slowly and painfully standing. “You’ll kill everyone, not just monsters if you get past me. But I WON'T let you do that.” A spear appeared in his hand, and though he still felt that he might collapse at any moment, he wanted to go out fighting. “I can feel everyone’s hopes and all their dreams. You’ll destroy them all if I die. That cannot happen.” A rush of determination flowed through MK, and the pain disappeared, replaced with energy. There was only a burning fire in him, in Undyne, holding them together with the determination to kill the human. He straightened his back and prepared to fight.

For once, the human showed surprise and fear. “Who _are_ you?

MK’s eyes hardened. He had thought about what he would say when he met the human in battle. But now all he could think of was how the human had talked about Gerson being wrong that there was no hero to strike him down. “I am the hero Gerson spoke of. I am Undyne the Second, and for the sake of the whole world… I will strike you down!” He grinned and narrowed his eyes, ready to do everything it would take to destroy the human. “You're gonna have to try a little harder than THAT.”

The fire in him was roaring now, a wildfire out of control. And in the middle of it all stood Undyne, cheering him on and adding fuel to the fire.

The walls Gerson had created disappeared.

The human got control of himself then and started attacking, kicking, trying to hit MK with the same pan he had almost used to kill Asgore. MK was ready, dodging and throwing spears that came at the human from every direction, even from below. They changed their tactics, MK changing his spears and the human his weapon. He held a toy dagger, which looked wicked enough, but MK’s spears split and divided as they advanced.

Every time the human wounded him, the fire within the monster grew, consuming everything in its reach. It was so big that it began to eat at MK himself, but he didn’t notice at first. The human did, pausing long enough to laugh that Undyne’s determination was so little that he couldn’t stop himself from melting.

Then MK changed. He felt himself altering, things popping out of his face, his armor melting and reshaping itself. He straightened, and the human’s face was filled with fear as he looked at MK, the hero of monsterkind whose only goal was to slay him. But he steeled himself and resumed the battle. In one hand was the dagger; in the other the pan. On his feet were old ballet shoes. A bandana adorned his head, an old tutu his waist. He said nothing, gritted his teeth, and advanced.

MK was waiting for him, drawing on his determination. In one hand he held a spear for close combat, and with the other hand he threw spear after multiplying spear at the human. Some spears had more than one spearhead. Sometimes they split in the air, and a few were pointed on both ends. Four or more spears, joined at the spear butts, spun like whirlwinds of death as they approached.

The human retaliated. When MK paused, he darted up and kicked him or stabbed him. A few times he even deflected the spears back at MK. But he was tiring, and wounded in many places. The whirlwind spears were fearsome things, dealing the most damage of any of MK’s attacks.

MK drew on his and Undyne’s determination even more, and his magic changed until the spears themselves seemed determined. When they missed the human, they turned around, none of them disappearing until they had hit him. The whirlwinds multiplied, razor blades of determination directed at him from every angle and side. Some spears were small, and falling from above like a rain of arrows. Others were so large it seemed that MK could ride them.

The human fell to one knee, then both knees. The spears kept flying. He toppled over, face first. After a moment, MK saw it. A red soul hovered above the dead human’s body. He reached out for it to give it to Asgore, but something else reached it first. A vine circled it and pulled it to its body.

MK found himself grabbing at nothing, the soul already absorbed into the… flower on the opposite side of the bridge. Now he was the one confused as he looked at the cheery flower with six yellow petals.  
“Where did you…?” MK sputtered.

The flower was transforming, its yellow petals and green stem melting together, forming something else. He was growing, looking less like a flower and more like a monster every second. Then he stopped changing, and before MK stood a little goat in a yellow-and-green striped shirt.

“Finally, I was so tired of being a flower,” he said, stretching. “Howdy! I’m Asriel.”

Asriel. Asgore’s son.

“...What?”

He sighed and looked away. “It’s a long story.”

Asriel pushed past MK and crossed the bridge to Asgore, face full of concern.

“Dad? Dad, are you alright?”

MK watched them, the hurt king with six human souls and the flower with one human soul, father and son, reunited at last. It felt like he was an intruder, and he retreated to the opposite side.

Nobody spoke. Some of the Royal Guard healed their wounded members in silence. The rest stared in silence, either at MK or Asgore and Asriel. Asriel was healing his dad, talking all the while. Asgore was also speaking, but his words were too faint to hear.

“No… Dad, you don’t understand. I talked to him, and he attacked me. I’m dying, I know it. I just wanted to say goodbye before I died. And I’m sorry. It’s my fault, isn’t it? I didn’t get six human souls when I went to the surface.”

MK motioned for the Royal Guard to give them some space. “I’m going to tell the monsters it’s over. Give Asgore and Asriel their space and the time they need.”

He walked back through Waterfall quietly, contemplating what had happened and talking with Undyne.

In Snowdin he paused and looked at his reflection in the water. His face had sprouted fins, or the equivalent of fins, and his teeth were sharper. Even his armor was different, pointed like Undyne’s. When he was melting or whatever, something strange had happened. He had felt his armor melt and reshape itself, not to mention things popping out of his face - the fins, probably, and he felt inseparably linked with Undyne. What had happened?

Alphys would know, but she would have to wait. MK kept walking. The monsters deserved to know that everything was over.

He tried the button code on the door, but evidently his family had lowered the bar on the other side, and the door wouldn’t budge. MK knocked.

“Who is it?” asked a clipped - if not worried - voice. MK recognized the voice.

“Doge, it’s Undyne.”

After another moment’s hesitation, the bar was raised and the door opened a crack. When she saw that he wasn’t the human, Doge opened the door fully and stood rigidly at attention.

MK stepped inside and raised his voice. “The human is dead. The Underground is safe again.” Cheers met that announcement. Some ran back to the forest without hesitation, while others approached him and asked for details.

MK stood in the middle, trying to learn his family’s side of the story as they asked for his. He only gave the basics, saying Asgore had fought and he jumped in when the king was about to die. As he still wasn’t sure what to think about Asriel, he said nothing about the prince.

Finally all the questions were over and everyone had started back to the forest. MK stood in the mysterious place for a long time, breathing in the smells and taking in the sights of the hidden refuge. It was peaceful here, though the footprints and shelters the monsters left behind looked out of place.

The Head of the Royal Guard stepped through the door and heard it shut behind him. Now he needed to get back to the other members of the Guard and Asgore. And Asriel, if he was still alive.

The only thing MK found was a note on the bridge:

_Went to New Home with the king & prince. Everything OK._

**Notes for the Chapter:**

> So MK just broke a bunch of science, huh. Here's some explanations for why some things worked:
> 
> With his and Undyne's determination combined, MK had more determination than Frisk, which was why MK could kill Frisk.  
> (Note that Frisk did not have the real knife or the locket, so something happened between Hotland and New Home that made him not want to go to New Home so much that he hung out in the Underground for another 6 months until he got bored and decided to go to New Home)  
> MK's fins will be explained in the next chapter.  
> And finally, Flowey. The way I explain it is that Flowey was fatally wounded a while back and had a little change of heart and wanted to see his dad before he died. Some people say that it takes 7 human souls to make him turn into Asriel; in this story it only takes one.


	5. Breaking the Barrier

It had been an eventful day. MK was exhausted. But warriors never rest. Not really. They were always on call, ready for any emergency. He trekked back through Hotland and the Core to New Home. The MTT Resort was active with the regular customers again, and there was talk of Mettaton having a new show.

Asgore wanted to see him.

“Thank you for saving me, Undyne,” he said.

MK shrugged. “It’s my job. What kind of Head of the Royal Guard am I if I do nothing when the King or any monster is in danger?”

“By the way, what happened to you?” the king asked, pointing to MK’s face and armor.

MK reached up and fingered his new fins, then his armor. “Um, frankly, your Majesty, I’m not sure. I was wondering if Alphys would know something about it.”

Asgore nodded contemplatively. “Would you mind visiting her? She hasn’t been responding when I call. I think it has something to do with the monsters that had been down there.”

“Sure, Asgore.” He turned to leave, then turned back, another question on his tongue. He didn’t want to ask, but he wanted to know the answer. “Oh, and Asriel? Is he…?”

Asgore nodded again, sadly this time.

“I’m sorry.”

“No, it’s fine. I’ll just need a little time.” Probably more than a little, now that he was certain both his wife and son were dead. “I’ve got the last soul,” he continued, “But… I don’t want to kill the humans. We’ve felt firsthand what it feels like for someone to want to eradicate your people.”

MK remembered when he had known that the human was a human, and a bad one at that. Even then he had looked for him, wanting to know if it was true and wanting to give him another chance. He hadn’t been one of the monsters who were hyped for the destruction of humanity, and frankly, it sounded interesting to live with humans, provided that they weren’t like the one MK had killed.

“Yeah, I get it, Asgore,” he replied. Asgore looked relieved.

“Alright, see you later.”

MK saluted and left the throne room.

He shed his armor and walked back through his New Home, the Core, MTT Resort, and down to the bottom level of Hotland this time at a much more leisurely pace than he had early that morning.

The lab door opened automatically. Alphys was nowhere in sight.

“Alphys? Dr. Alphys?” he called. He waited half a minute and called again, but still there was no reply. MK frowned.

 _Do you know where she would be, Undyne?_ He asked.

Undyne hesitated. She would usually hear the door open and come down from her room, but…

_Asgore said she wasn’t responding to his calls._

She almost always answers the phone! I mean, unless she’s sleeping or something, and she wouldn’t be at this hour.

The only thing to do now was explore.

 _Where do you think she would be?_ MK asked.

You could check her room… It’s up that escalator.

He stepped onto the up escalator and let it carry him to the only room on the second floor. He scanned the room and quickly saw that it was deserted, save for the random unusual gadgets that cluttered the walls.

Even Undyne seemed uncertain now. If she’s not here… I can’t think of any other place where she would be!

 _There aren’t any other rooms here? Just downstairs and her bedroom? That doesn’t sound right,_ MK argued. He took the down escalator, still thinking.

She was always quiet, kinda nervous… But I didn’t think it was bad enough for her to disappear like this!

_Where else could she go? Do you think she would have left the Lab?_ MK asked.

No, I don’t think she’d leave…

_Then she would have a secret room somewhere._ MK walked along the uncluttered wall of the main floor and felt the wall for a secret panel. Seeing the hole on the other side, he paused his wall check and moved to the hole. It was only a few feet wide, and there was nothing secret about it.

Beside it was something that he had always thought was a door, but he had never seen it open, so after a while he assumed it was there to complete the look like the hole.

Only this time, the door opened on his approach. MK hesitated, now wondering where it led and what Alphys had hidden behind the door that she had been so careful to not let people see or have access to.

He stepped inside, alert for anything unusual, but there was nothing. He was in an elevator. There was only one other level button, so he pressed it and heard the door behind him shut softly.

It was only a few seconds before a speaker somewhere in the elevator began blaring:

“WARNING! WARNING! ELEVATOR LOSING POWER! EM TETHER STABILITY LOST! ALTITUDE DROPPING!”

The elevator began hurtling down, and all MK could do was brace for the impact and hope that he would be okay.

A squealing of brakes sounded through the shaft and they slowed, though it wasn’t enough to stop the elevator. With a large crash it landed at the bottom of the shaft. MK lost his balance and rolled across the floor.

Are you okay? Undyne asked.

He got to his feet and stretched, testing his limbs.

 _A little bruised, but I don’t think anything’s broken,_ he responded. He pushed the “Door Open” button, but nothing happened.

_Guess I’ll have to force it open._

A spear helpfully appeared in MK’s hand. Wedging the point of it between the two doors, he slowly pried them apart. They wouldn’t stay open on their own, so he used a couple more spears to hold the doors open. When he had shoved them far enough apart, he slipped between them and removed the spears preventing their closure. They closed with a quiet clang, and everything was silent in the dark place.

 _So where are we?_ MK asked Undyne. _Have you ever been here or anything?_

I guess we’re under the lab, but I don’t know what we’ll find here. Alphys never said anything about this place.

The eerie silence was unsettling, but it was better with Undyne to keep MK company. He wandered the lab and tried to learn what had happened from Alphys’ entries placed on the wall. Unfortunately, they were out of order and scattered all over the lab. Apparently she had injected determination into fallen monsters, hoping to preserve the souls and slowly accumulate soul power to break the barrier instead of waiting for more humans to arrive. But instead of dying, the monsters started to recover.

MK walked down a hallway and heard breathing. He entered the room and discovered it was a dormitory. Alphys was there, sitting on a bed, her head in her hands, giving no indication that she had heard anyone come in, but she looked up when he approached the bed.

“H-hiya.” was all she could manage.

MK sat down beside her. “Hey, Alphys. Asgore was getting worried about you.”

She didn’t reply.

“And he was wondering if you could run some tests on me. Find out why I got fins and sharp teeth during the battle.”

She spoke. “I was w-watching you. Fight, I mean. I-I’ve never seen anything l-like that before!”

“Yeah. So do you know why I’m like this, or do you have any ideas?”

“W-well, I don’t know. M-monsters aren’t supposed to be able to absorb other monster souls, b-but you did. M-maybe you were both determined enough that it worked somehow.”

“Alright, but what about what happened in the battle? I was… melting, and then I got fins and teeth and kept fighting. And my armor changed, too.”

“Oh! Y-yeah, I saw that. Um, I think y-you were melting because of all your determination. M-monsters’ bodies can’t handle that much determination. The fins and teeth… I want to run some tests on your souls. I-I think maybe you had so much determination that your soul and Undyne’s m-melted together a little, like the monsters down here did, b-but it was your souls, not your bodies. I-I’m not really sure, though. I want to run some tests on you.” Alphys stood up. “And th-thanks for finding me, Undyne, but I’m not ready to leave.”

“Take your time, Alphys,” MK assured her. “I think we’ll both be here awhile.”

She restored the power, fixed the elevator and they returned to the main floor, where she promptly locked the doors. She didn’t feel ready to have any other visitors. 

A week of tests and anime passed before Alphys was satisfied. Her tests confirmed her theories, although she was still a little confused about it. MK just accepted what she said. He had never been into science.

When Alphys wasn’t running tests, she told him the rest of the story:

The fallen monsters started recovering, but then they melted into each other. She kept them down here, afraid to return them to their families, who were constantly asking when they would come home.

At the same time, Alphys had been injecting determination into a flower from the surface that she found in Asgore’s garden, hoping that it would be able to hold the monster souls. It didn’t seem to do anything, but one day it disappeared. MK put a few and three together and theorized that it was the flower Asriel had been.

MK understood why Alphys had done what she had done. She was ready to leave now, to tell the truth to everyone who hadn’t heard it yet, especially the families of the melted monsters.

He returned to New Home, where Asgore called him into his throne room again. “Are you ready?” the king asked.

“For the barrier to be broken? Never been readier, Majesty.”

Asgore smiled and walked through the doorway by the covered throne. MK followed. In the barrier cavern, the king faced him. “It’s time for everyone to go free.” MK watched, openmouthed, as Asgore rose into the air. The seven souls rotated around him, and at the snap of his fingers, they flew at the barrier.

There was a blinding flash of light, causing MK to shield his eyes. When he lowered his arm, the souls were gone. Light hit him and made him squint. It was the light of the warm sun. They were free.

Asgore stood there for a long time, looking at the Surface for the first time since the barrier had been created. Finally he turned to MK again. “Would you and Alphys mind getting everyone together so we can leave?”

“Sure, Asgore.”

Monsters said afterwards that the news of the barrier breaking spread faster than the Undernet. In an hour or two, everyone was more than ready to leave, each with the things they thought they would need on the Surface, which they had prepared in the week that MK and Alphys had been in her lab.

Asgore was at the head of the monsters when they left. There would be many challenges on the Surface, some new, some they were familiar with. But they were confident they could overcome them. After all, did they not have their hero with Undyne’s soul among them? Undyne II, who overcame a fatal blow to defeat the human, would protect them, as he had before.

**Notes for the Chapter:**

> EDIT: This is now canon to the story [When Undyne Called](https://archiveofourown.org/works/22091332).


End file.
